Tool grinding machine



March 6, 1951 5, 5, MADER 2,544,604

TOOL GRINDING MACHINE Filed May 3, 1947 9 Sheets-Sheet 2 W/IIIIIII'J Zhwentor Stewart 5. Made- MUM we. ammeg arch {1951 s. s. MADER 2,54 0

TOOL GRINDING MACHINE Filed May'S, 1947 l 9 Sheets-Sheet 3 March 6, 1951 s. s. MADER TOOL GRINDING MACHINE 9 Sheets-Sheet 4 Filed May 3, 1947 3 two/whom Stewart 5. Mader March 6, 1951 s. s. MADER TOOL GRINDING momma 9 Sheets-Sheet 5 Filed May 3, 1947 TIIIA a m M 5 w W e um LID.

March 6, 1951 s. s. MADER 2,544,604

TOOL GRINDING MACHINE Filed May 3, 1947 '9 Sheets-Sheet 6 March 6, 1951 s, 5, MADER 2,544fi0 -E TOOL GRINDING MACHINE Filed May 3, 1947 9 Sheets-Sheet 7 4IIIlIIIIII/IMMMMIIIIIIIMfi/lIIba- 1N VEN TOR.

Stewart 5. Mader 9 Sheets-Sheet 8 Filed May 3, 1947 I H II Ill llllllllllllll #9, Stewart SMacier March 6, 1951 s. s. MADER TOOL GRINDING MACHINE 9 Sheets-Sheet 9 Filed May 3, 1947 Patented Mar. 6, 1951 TOOL GRINDING MACHINE Stewart S. Mader, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation oi Massachusetts Application May a, 1947, Serial No. 745,799

4 Claims.

This invention relates to grinding machines and more particularly to a tool grinding machine.

One object of the invention is to provide a simple and thoroughly practical grinding machine for grinding edge or cutting tools with predetermined clearance and rake angles. Another object of the invention is to provide an improved tool grinding machine in which the grinding 1 wheel rotates ,and oscillates while the tool is sup ported in a tool holder with a master form or template arranged to control the movement of the holder so that the tool being ground is ground with predetermined clearance angles and to a predetermined shape.

Another object of the invention is to provide an improved tool grinding machine in which a master tool may be readily ground to predetermined specifications as to shape and clearance angles. Another object of the invention is to provide an improved tool grinder in which a master tool may be first formed to a predetermined shape and contour after which a template may be ground and the template thereafter used to grind new cutting tools and to regrind worn cutting tools to the predetermined specifications. Another object of the invention is to provide an imimproved tool grinder with a clearance setting gage to facilitate setting the tool holder 50 that predetermined clearance angles may be ground on a master tool. Another object of the invention is to provide an improved tool holder with a protractor head to facilitate grinding predetermined edge angles onthe master tool to be ground. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplitied in the structure tobe hereinafter described, and the scope of the application of which will be indicated in the following claims.

One embodiment Of the invention has been illustrated in the accompanying drawings, in which like reference numerals indicate like parts and wherein:

.Fig. 1 is a front elevation of the improved tool grinding machine;

Fig. 2 is a vertical sectional view taken approximately onthe line 2-2 of Fig. 1, showing the lower portion of the base in elevation;

Fig. 3 is avertical sectional view, on a reduced scale, taken approximately on the line 3-3 of Fig. 2, showing the adjusting mechanism for adjusting the tilt of the work table;

Fig. 4 is a vertical sectional View, on an enlarged scale, taken approximately on the line 4-4 of Fig. 2, showing the motor driven mechanism for rotating and 1'01 oscillating the grinding wheel;

Fig. 5 is a fragmentary cross sectional view, on an enlarged scale, taken approximately on the line 55 of Fig. 4, showing the manually operated cam mechanism for starting and stopping the wheel spindle oscillation;

Fig. 6 is a fragmentary plan view of the tool grinding machine, on an enlarged scale, with the wheel head removed and parts of the base broken away and shown in section to more clearly illusgate the wheel feeding and adjusting mecha- Fig. "I is a side elevation, on an enlarged scale, of the tool holder showing the protractor in an. operative position;

Fig. 8 is a horizontal sectional view taken approximately on the line 8-4! of Fig. 7, through the tool holder;

Fig. 9 is a fragmentary plan view showing the protractor head;

Fig. 10 is a fragmentary front elevation, on an enlarged scale, showing the clearance gage setting mechanism;

Fig. 11 is a right hand end elevation of the clearance edge setting mechanism as illustrated in Fig. 10;

Fig. 12 is a plan view of the clearance gage setting mechanism;

Fig. 13 is a vertical sectional view, on an enlarged scale, through the table adjusting mechamsm;

Fig. 14 is a diagrammatic view showing the manner of adjusting the master tool relative to the template to generating a radius on the template which is tangent to the two cutting faces of the tool;

Fig. 15 is a diagrammatic view showing the tool holder set upon the step block in position for grinding the template;

Fig. 16 is a similar diagrammatic viewshowing the tool holder in position on the table for grinding the tool after the template has been previously generated, and

Fig. 1'? is a. fragmentary vertical sectional view, on an enlarged scale, through the grinding wheel, wheel guard and truing apparatus.

An improved tool grinding machine has been illustrated in the drawings comprising a base I5 which supports. a pivotally mounted work table IS. The work table I6 is supported by a pair of aligned pivot studs l1 and 18. The studs l1 and To facilitate adjustment of the table IS, a vertically arranged adjusting screw 2| is slidably supported in a cylindrical aperture 22 and a cylindrical aperture 23 formed in a pair of spaced brackets 24 and 25 which are fixedly mounted relative to the base l5. A key 26 (Fig. 13) which is fixedly mounted within the bracket 25 engages a key slot formed in the periphery of the screw 2|. A ball 21 is supported adjacent to the front edge of the work table IE on its underside in alignment with the upper surface of the screw 2|.

To facilitate adjustment of the screw 2| a manually operable hand wheel 28 is mounted on the right hand end of a rotatable shaft 29 (Fig. 13). The shaft 29 is rotatably journalled in anti-friction bearings 39, 3| and 32. The left hand end of the shaft 29 supports a bevel gear 33 which meshes with a bevel gear 34. The bevel gear 34 is rotatably supported by an antifriction bearing 35. The bevel gear 34 has an upwardly extending integral hub 36. The inner aperture of the bevel gear 34 and the hub 36 is threaded to mesh with the thread on the screw 2|. It will be readily apparent from the foregoing disclosure that rotation of the hand wheel 28 will be transmitted through the mechanism above described to raise or lower the screw 2| and thereby to adjust the position of the work table |6 so that it may be positioned in a horizontal plane or if desired adjusted to a predetermined angular position. i

To facilitate precise adjustment of the table IS, a bracket 38 is fastened to the lower end of the screw 2| (Fig. 2) The bracket 38 is provided with a vertical extension which is formed as a graduated scale 39 (Fig. 1). A vernier 49 is formed on a plate 4| which is fastened to the front of the machine base l5. Thevernier scale 40 is arranged beside the graduated scale 39. By use of the graduated scale 39 and the vernier scale 49, the table II; may be precisely adjusted either into a horizontal plane or at an angle thereto as desired.

A transversely movable wheel slide 45 (Fig. 4) is arranged to slide transversely relative to the base IS on a dovetailed slideway 46. The wheel slide 45 serves as a support for a rotatable grinding wheel 41.

The wheel slide is arranged so that it may be fed transversely relative to the base l by means of a suitable feeding mechanism which may comprise a half nut 48 depending from the underside of the slide 45. The half nut 48 meshes with a rotatable cross feed screw 49. The cross feed screw 49 is journalled in anti-friction bearings 56 and 5| mounted in the base l5 of the machine.

To facilitate adjustment of the wheel slide 45, a manually operable feed wheel 52 is mounted on the forward end of a rotatable shaft 53 (Fig. 6). The shaft 53 is supported in anti-friction bearings 54 and 55 which are in turn flxedLv mounted relative to the base l5. The shaft 53 is provided with a sprocket 56 which is connected by a link chain 51 with a sprocket 59 which is keyed to the forward end of the feed screw 49 (Fig. 6). An idler sprocket 59 is rotatably supported on a stud 69 to facilitate taking up slack in the link chain 51.

The grinding wheel 41 is supported. on the right hand end of a wheel spindle 62 (Fig. 2).

4 The wheel spindle is rotatably supported in bearings (not shown) mounted in the cylindrical cartridge 63. This cartridge 63 is one of the standard wheel mountings now available on the market which contains suitable bearings and a wheel spindle supported thereby. It is therefore not deemed necessary to illustrate and describe in detail the bearing structure contained within the cartridge 63. The cartridge 63 together with the spindle 62 and grinding wheel 41 are supported in' a pivotally mounted frame 64. The frame 64 is pivotally supported on a rock shaft 65 which is'in turn supported on the wheel slide 45.

A driving motor 68 is mounted on top of the wheel head (Fig. 2). The motor armature shaft 69 is provided with a multi-V-groove pulley 10 which is connected by a pair of V-belts with a multi-V-groove pulley 12 mounted on the left hand end of the wheel spindle 62. An idler pulley 13 (Figs. 2 and 4) serves to take up the slack in the driving belts II. It will be readily apparent from .the foregoing disclosure that when themotor 68 is started, a rotary motion will be imparted through the driving mechanism above described to rotate the wheel spindle 62 and the grinding wheel 41.

In order to facilitate the grinding of cutting tools, it is desirable to transmit not only a rotary motion to the cutting tool but also an oscillating motion. so that the tool may be ground without the necessity of moving the tool relative to the wheel face during the grinding operation. This is preferably accomplished by an oscillating mechanism comprising a cam 15 which is mounted on the lower end of a vertical shaft I6 (Fig. 4). The shaft 16 is supported in anti-friction bearings l1 and 18 supported in the wheel slide 45. A worm gear 19 is mounted on the upper end of the shaft 16 and meshes with a worm 89. The worm 89 is mounted on a horizontal shaft 9| (Figs. 2 and 4). A V-groove pulley 62 is mounted on the left hand end of the shaft 8| (Fig. 2) which is connected by a v-belt 83 with the motor pulley III. The pivotally mounted frame 64 which supports the wheel spindle 62 is provided with a plate (Fig. 4) which is normally maintained in engagement with the cam 15 by means of a compression spring 86 which is interposed between a portion of the wheel slide 45 and a stud projecting from the frame 64. It will be readily apparent from the foregoing disclosure that when the motor 68 is started, a rotary motion will be transmitted through the mechanism above described to rotate the cam 15 and thereby to transmit an oscillating motion to the frame 64, the wheel spindle 62, and the grinding wheel 41. I

During a wheel truing operation and in setting up the machine, it is desirable to stop the oscillation of the grinding wheel. This may be accomplished by means of a cam 99 (Fig. 5) which is pivotally supported by a stud 9|. The stud 9| is fixedly mounted relative to the wheel slide 45. A manually operable handle 92 is fixedly mounted relative to the cam 99. During the normal operation of the machine, the cam 99 and handle 92 are in dotted line positions 99a and 32a (Fig. 5). I In this position of the parts the frame 64 is free to oscillate without interference of the cam 99. When it is desired to stop the oscillation of the frame 64 and the grinding wheel 41, the handle 92 is moved from position 92a in a clockwise direction into full line position 92 which serves to shift the cam 99 into the full line position (Fig. 5). During this movement the cam 90 engages the plate 05 on the frame 34 and swings the plate 35 on the frame 54 and swings the frame 54 in a counterclockwise direction (Fig. 4) against the compression of the spring 35 so that plate 95 is out of engagement with the cam 15 so as to prevent an oscillating movement of the frame 64 and the grinding wheel 41.

The grinding wheel 41 is surrounded by a cylindrically shaped wheel guard 95 (Fig. 17) which is fixedly mounted relative to the base I5. A guard cover 96 is rotatably supported by the wheel guard 95 and is provided with an opening to expose a predetermined portion of the operative face of the grinding wheel 41 as shown in Figs. 1 and 3. At the lower portion of the cover 95, a slot 91 extends across the remaining portion of the cover so that a chordal path across the face of the grinding wheel is exposed to facilitate grinding a master template as will be hereinafter described.

The driving motor 68 is preferably a reversible motor which is arranged to drive the grinding wheel 41 in either direction so that a grinding operation may be performed on either side of the wheel axis and the wheel driven in the desired direction. To facilitate grinding on. the right hand portion of the grinding wheel 41 (Fig. 1), the guard cover 96 may be rotated 180 relative to the guard 95 (Fig. 17) so that the wide open portion of the cover plate 95 will expose the right hand portion of the operative face of the grinding wheel 41.

It is desirable to provide a grinding wheel truing apparatus which is arranged so that'the operative face of the grinding wheel may be maintained in a predetermined location relative to other parts of the machine to be hereinafter described. As shown in Fig. 17, a rock shaft I is supported in anti-friction bearings IOI and I02. The right hand end of the rock shaft I00 supports a rock arm I03. The lower end of the rock arm I03 is provided with a diamond truing tool I04. The diamond truing tool I04 is supported in a cylindrical aperture formed in the lower end of the rock arm I03 and is clamped in adjusted position therein by means of a set screw. To facilitate adjusting the diamond truing tool to compensate for wear on the diamond truing tool, an adjusting screw I05 is provided by means of which the diamond may be adjusted toward or from the operative face of the grinding wheel 41. A look nut I05 is provided to facilitate locking the screw I05 in adjusted position. A manually operable handle I01 is mounted on the end of the adjusting screw I05 to facilitate a manual swinging of the truing tool I04 across the operative face of the grinding wheel 41.

In order to facilitate accurate grinding of cutting tools to predetermined shapes, it is desirable to provide means whereby a template and the cutting tool may be precisely adjusted relative to the operative face of the grinding wheel 41. As illustrated in the drawings (Fig. 17) a 1 calibrating block I08 having a plane operative face is provided. This calibrating block may be utilized in setting up a tool to be ground in the tool holder or may also be utilized in grinding a template from a master tool. The face of the calibrating block I08 when swung to a downward position (Fig. is preferably located two inches forward of the operative face of the grinding wheel 41. A stop barIIIO (Fig. 17) is mounted in a groove formed in the base I5 and is held in fixed position relative thereto by means of a plurality of set screws III and III. The face of the stop bar I is arranged two inches to the rear of the operative face of the grinding wheel 41. The operative face of the grinding wheel therefore in its normal position lies in a plane midway between the operative face of the callllia'gting block I03 and the face of the stop bar To attain one of the objects of this invention an improved tool holder is provided such as for example that shown in my pending patent application, Serial No. 652,880 filed March 8, 1946 (U. 8. Patent No. 2,475,796, dated July 12, 1949). The improved tool holder II5 as shown in Figs. 7, 8, 15 and 16 is provided with a base IIG which is formed as a plane surface so that it may be readily moved in any direction on the work table I0. The base H8 is provided with an upwardly extending dovetailed siideway II1 which mates with a correspondingly shape siideway formed on a transversely movable slide iii. A nut and screw adjusting mechanism is provided (Fig. 8) for precisely adjusting the position of the slide II5 relative to the base II5. As illustrated in the drawings, a rotatable screw H9 is supported by the slide H8 and meshes with a nut I20 carried by the base IIO. A pair of knurled adjusting knobs I2I and I22 are mounted on opposite ends of the feed screw II9 (Fig. 8). The slide II: is provided with two integral upwardly extending arms I23 and I24 which serve as a support for a frame I25. The frame I25 is provided with a pair of trunnion studs I25 and I21. A pair of clamping screws I 25 and I29 pass through arcuate slots I30 and I 3| formed in the upwardly extending arms I23 and I 24 respectively and which screw thread into the frame I25. It will be readily apparent from the foregoing disclosure that the frame I25 may be pivotally adjusted relative to the upwardly extending arms I23 and I24 by loosening the knurled nuts I32 and-I33 on the clamping screws I28 and I29, swinging the frame I25 to the desired angle after which the knurled nuts I32 and I33 may be again tightened to clamp the frame I25 in the desired adjusted position. As illustrated in Fig. 7, a calibrated scale I34 is mounted on the frame I25. An index point is provided on the arm I24 to facilitate readily adjusting the frame I25 to a predetermined angular position.

The frame I25 serves as a support for a rotatable sleeve I35 which is supported in a cylindrical bore I36 formed within the frame I25. A clamping screw I31 is provided on the frame I25 to facilitate clamping the sleeve I35 in the desired adjusted position.

A hollow tool supporting sleeve I38 is slidably keyed by means of a key I39 within a cylindrical bore formed within the sleeve I35. The sleeve I39 is provided with a square shaped tool supporting aperture MI. The sleeve I38 is provided with a threaded portion I42 which meshes with or engages with a threaded knurled collar I43. The collar I43 is provided with an integral flange I44 which serves as an end thrust member to allow rotation of the collar I42 but arranged to prevent endwise movement thereof. In order to hold the flange I44 against endwise movement, the flange I44 is located between a surface I45 formed on the end of the sleeve I35 and a flange I45 formed integral with a collar I41 which is screw threaded onto the 1s sleeve I35. The surface I45 and the flange I43 serve to engage opposite faces of the flange I44 so as to prevent endwise movement thereof. It will be readily apparent from the foregoing disclosure that the knurled nut or collar I43 may be retated to produce an axial feeding movement of the sleeve I38 so as to facilitate an ad ustment of the sleeve I36 relative to the base 6 and the slide II6.

To facilitate clamping a cutting tool within the square shaped aperture III of the sleeve I36, a plurality-of threaded holes I49 are provided in the sleeve I38 (Fig. 7). One or more clamping screws I50 may be placed in the desired threaded holes I49 so as to clamp a cutting tool I48 rigidly in position in the desired location within the square shaped aperture I4I.

In order to facilitate locating the tool holder slide II8 relative to the tool holder base II5, a locating stud I52 is provided. The locating stud is arranged to be inserted in a hole half of which is formed in the underside of the slide H8 and the other half of which is formed in the tool holder base II6. A clamping screw II is provided (Figs. 7 and 8) to lock the tool holder slide II8 relative to the tool holder base H6.

The base of the tool holder H6 is formed with a forwardly extending portion I53 which serves as a support for a template I54 or a protractor head I55. The template I54 and the protractor head I55 are arranged to be interchangeably clamped to the tool holder when desired. The protractor head I55 may comprise a base portion I56 which is located in a predetermined relationship on the projection I53.

by a plurality of dowel pins or studs (Fig. '7). The protractor head I55 is provided with an adjustably mounted straight edge I51 which is arranged to pivot about a stud I58. A graduated dial I59 which is fixedly mounted relative to the straight edge I51 serves to facilitate adjustment of the straight edge to the desired angular position. A vernier scale I66 is mounted also to facilitate grinding corresponding angular faces on a. master template as will be hereinafter described.

To facilitate setting up the tool holder H5 or grinding predetermined clearance angles on the face of a cutting tool, a clearance gage apparatus is provided comprising a bracket I65 which is adjustably mounted on a slideway I66 formed on the side face of the wheel guard 95. The bracket I65 is provided with an elongated slot I61. A threaded stud I66 passes through the elongated slot I61 (Fig. 11) and is screw threaded into the wheel guard 95. A knurled nut I69 is provided on the threaded stud I68 to facilitate clamping the bracket I65 in the desired position relative to the wheel guard 95.

tally extending portion I10 which is in turn provided with an elongated slot In (Figs. 10 and 11). The elongated slot I1I serves as a guide for a transversely adjustable slide I12. The slide I12 is provided with an integral flange portion I13 which slides on the upper surface of the horizontal pro ection I10. A sleeve I14 is rotatabiy supported within a central aperture formed in the slide I12. The sleeve I14 is provided with an integral flange I15. A rotatably mounted disc I16 is mounted above the integral flange I15 and is provided with an integral stud I11- which passes through a central aperture formed in the sleeve I14. The lower end of the stud I11 is threaded and is provided with a knurled clamping nut I16 (Fig. 10) by means of which the disc I16, the integral flange I15, and the slide I12 may be clamped in adjusted position relative to the horizontal arm I16. The integral flange I15 is provided with a scale I19 which is graduated in degrees. The disc I16 is similarly provided with a scale I which is also calibrated in degrees. An index or zero marker I8I is fixedly mounted on the flanged portion I13 of the slide I12 and serves to facilitate angular adjustment of the integral flange I15 and the disc I16.

The integral flange I15 is provided with a vertically extending arm I62 which serves as a support for a horizontally arranged stud I83 (Fig. 10). The stud I83 is provided with a threaded portion I64. A winged nut I85 is provided to facilitate clamping the stud I63 in adjusted position relative to the arm I82. The stud I83 is provided with a slabbed-off plane surface I66 which serves as a support for a plane surfaced gage vane I81. A screw I66 and a winged nut I69 serve to clamp the gage vane I61 on the stud I63. The stud I83 is provided with a fixedly mounted indicator arm I and the vertically extending arm I82 is provided with a graduated scale I9I to facilitate adjusting the gage vane to the desired angular position as will be hereinafter described.

The disc I 16 is similarly provided with a vertically extending arm I92 which supports a horizontally arranged stud I93. The stud I93 is provided with a threaded portion I94 having a winged nut I95 by means of which the stud I93 may be clamped in adjusted position relative to the arm I92. The stud I93 is provided with a slabbed-oif plane surface I96 which serves as a supporting surface for a plane surfaced gage vane I91. A screw I98 and a winged nut I99 serve to facilitate clamping the gage vane I 91 to the stud I93. The stud I93 is provided with a fixedly mounted downwardly extending indicator arm 200. The vertically extending arm I92 is provided with a graduated scale 2(II which is calibrated in degrees to facilitate adjusting the position of the gage vane I91 to the desired and predetermined angular position as will be hereinafter described. I

The bracket I65 is provided with a vertically arranged portion 202 (Figs. 10 and 11) which is provided at its lower portion with a plane reference face 263 which serves to facilitate setting up the tool holder in a manner to be hereinafter described.

"To facilitate a wet grinding operation, a motor driven pump (not shown) is provided for conveying coolant fluid to the grinding wheel 41 during the grinding operation. This pump driving motor is controlled by a push button start switch 266 and a push button stop switch 261 mounted on the front of a motor control panel (Fi 1).

To control the driving motor 68, a push button start switch 208 and a push button stop switch 209 are mounted on the front of the control panel (Fig. 1) to facilitate starting and stopping the motor 68 as desired. The motor 68 is a reversible type motor which serves to permit rotation of the grinding wheel 41 in either direction as desired. The direction of rotation of the motor 68 is controlled by a reversing switch 2I0 (Fig. 1) which is also mounted .on the front of the electric control panel.

A precision means including a hand wheel 28 and a screw 2| (Figs. 1, 3 and 13) is provided for adjusting the tilt of the table I6 so that it may be positioned horizontal or tilted relative thereto when desired. In grinding round nose and parting or cut-off tools where a predetermined front clearance angle and also side clearance angles are to be formed, the table I6 is precisely tilted to a predetermined angle for generating side clearance angles and the tool holder II5, frame I25 is tilted (but not rolled) to a predetermined angle so that the sum of the angle of the table I 6 and the tilt of the tool holder frame I25 equals the front clearance angle to be ground on the tool. In the grinding of other tools, the table is set horizontal and the tool holder frame I 25 is tilted and sleeve I 35 rolled to predetermined angles to produce the predetermined clearance angles on the tools being ground.

Operation The operation of the improved tool grinding machine will be readily apparent from the foregoing disclosure. Assuming that it is desired to grind a master tool in accordance with predetermined specifications, including edge angles and clearance angles. A master tool blank I48 is mounted in the tool holder II5, that is, it is inserted in the square-shaped aperture MI in the sleeve I38 and is clamped in a predetermined position therein by means of clamping screws I50. The protractor head I55 is attached to the projection I53 of the tool holder H5 and the protractor blade I51 is adjusted to a-.predetermined angular position for grinding one of the edge angles on the master tool blank I 48. The tool holder H5 is moved on the table I6 to position the protractor blade I51 in operative engagement with the stop bar I09. The table I6 is set horizontal and the tool holder set at zero degrees tilt and zero degrees roll so that right angle edge face will be ground on the end of the master tool blank I48. The master tool I48 may be fed toward the rotating and oscillating grinding wheel 41 by means of the knurled nut or collar I43 until an edge angle of the desired length is ground on the end face of the master tool blank I48.

The blade I51 of the protractor I55 is then angularly adjusted and set for grinding the second edge angle on the master tool blank I48. The tool holder H5 is moved on the table I6 to position the blade I51 in engagement with the stop bar I09. The master tool blank I48 is fed toward the rotating and oscillating grinding wheel 41 until a second edge angle of the desired length is ground on the master tool blank I48.

The protractor blade I51 then is set at zero degrees position. The clearance gauge bracket I65 is adjusted vertically to the proper position so that when the tool holder II5 ismoved on the table I6 so that the protractor blade I51 is adjacent to the reference face 203, the clearance iacent to the edge angle faces on the master tool blank I48. The clearance gauge vanes I81 and I91 are angularly adjusted and positioned for negative relief angles equal to the clearance or relief angles to be ground on the master tool I48. If negative clearance or relief angles are to be ground on the master tool I48, then the clearance gauge vanes I81 and I91 are adjusted to positive angles equal to the negative angles to be ground. The edge angle dials or disks I15 and I16 are loosened by means of the knurled nut I18 so that the slide I12 may be adjusted laterally and so that the clearance gauge vanes I81 and I91 are free to swing about the axis of the stud I11. The tool holder H5 is moved on the table I6 to position the protractor blade I51 in engagement with the reference face 203. The master tool I48 is then fed toward the gauge vanes I81 and I91 by means of the knurled nut or collar I43. During the forward movement of the master tool I48, the frame I25 is tilted and the sleeve I rolled until the full areas of edge angle faces of the master tool I48 coincide with the plane faces of the clearance gauge vanes I81 and I91 respectively. The knurled nut I18 is then actuated to lock edge angle dials or disks I15 and I16 and the gauge vanes I81 and I91 in adjusted position.

The angular setting of the edge angle dials or disks I 15 and I16, together with angle of tilt of frame I25 and roll of the sleeve I35 are then noted for future reference.

The clearance or relief angles on the master tool I48 are then ground. The protractor blade I51 is adjusted to an angular setting corresponding with the reading on the disk scale I19 (Fig. 10) after which the tool holder H5 is moved on the table I6 so that the protractor blade I51 engages the stop bar I09 while the clearance angle I48a. is ground. The tilt of the tool holder frame I25 and the roll of the sleeve I35 remain fixed during this grinding operation. The protractor blade I51 is then adjusted to an angular setting corresponding with the reading on the disk scale I80, after which the clearance or relief angle I48b is ground. Having set the square ground master tool blank to negatively positioned gauge vanes I81 and I91 and then grinding these faces against a vertical plane faced wheel, the result is relief angles of a positive character are produced.

A master template is then produced while using the master tool as a template. The protractor head I55 is then removed from the tool holder I I5 and a master template blank I54 mounted thereinstead. The tool holder slide H5 is locked in a center position by means of the locating pin or stud I52 and the clamping screw I5I (Figs. 7 and 8) The tool holder H5 is then positioned on a step block 205 (Fig. 15). The arm I03 is then swung to position the calibrating or reference block I08 as shown in Fig. 15. The template I54 is then ground while moving and maintaining the master tool I48 in engagement with the reference block I08. Due to the fact that relief faces HM and I 481) on the master tool I48 intersect forming a sharp point or line and due to the fact that the face of the reference block I08 is spaced 2" in front of the operative face of the grinding wheel, a 2" radius will be generated on the template I54 which is tangent to the edge faces I54a and I54b.

The machine is now set up to generate a predetermined radius on the master tool I48. By manipulation of the hand wheel 52 and feed 11 screw 40, the wheel slide 45 and the grinding wheel 41 are backed-off in a direction away from the operator and toward the stop bar I08 by an amount equal to the radius to be generated on the master tool I48. The tool holder II5 is then positioned on the table II with edge I54a of the template I54 in engagement with the stop bar I09 (Fig. 16), thus positioning the master tool I48 in the full line position (Fig. 14). By rotating the tool holder II5 in a clockwise direction, maintaining the template I54 in contact with the stop bar I09, the master tool I48 will pivot about point A and pass through an angle equal to the supplement of the included angle of the two cutting edges. In this case 90 although it can be any angle from to any angle less than 180 within the limits of physical interferences of the tool holder II and the wheel guard 85 and the uard cover 80.

In order to grind a radius tangent to both the cutting edges HM and lb of the master tool I40, the tool must be positioned so as to have both cutting edges equally distant from the axis of rotation A as measured in directions normal to the edges I481: and I48b by the amount of the radius desired. The master tool I48 will then occupy the dotted line position (Fig. 14). Consequently the tool I48 must be adjusted along a line 0-0 until the point A lies at AI. As the tool I 48 may be adjusted forward relative to the tool holder II5 along a line YY to the amount AB and the tool holder slide II8 adjusted laterally relative to the tool holder base I It by means of the adjusting screw II8 along a line X--X to the amount B-AI, these movements or adjustments will result in adjusting the tool I48 along the line CC to the amount A-AI, this bringing the tool I48 into the required dotted line position (Fig. 14).

The practical way to accomplish these adjustments, and accurate within standard to plus .001", is as follows: With the tool holder II5 in position so that the edge I540 of the template I54, corresponding to the front cutting edge I48a of the master tool I48, is abutting the stop bar I08, advance the tool I48 in the tool holder II5 along line Y-Y until the front cutting edge I40a just contacts the operative face of the grinding wheel 41 in the wheel's adjusted position. Then rotate the tool holder II5 clockwise through an angle equal to the supplement of the included angle of the tool cutting edges I 48:: and H81: as determined by the template I54. It will be found that the side cutting edge I48b with the holder II5 rotated to the new position is still a distance from the face of the grinding wheel 41. By means of thescrew II8, the tool holder slide H8 is moved laterally relative to the base II5 until the side cutting edge lb of the master tool I48 moves part way to the wheel. This adjustment, being in the direction of line X-X and at an acute angle with the plane of the wheel face, will withdraw the front cutting edge I48a of the tool I 48 away from the wheel. This retracting of the front cutting edge I48a from the wheel face 41 must be corrected by readjusting the tool forward in the tool holder I I 5 with the holder in the same position as when this adjustment was made previously. The forward adjustment of the tool I48 automatically advances the side cutting edge H81) in the direction necessary for it to contact the wheel face when the holder is in the rotated position. This explains why it is necessary to ad ust the holder slide I I8 laterally until side cutting edge 1481: of the tool I40 is only part way to the wheel face in the initial lateral adjustment. 3! alternately making these adjustments, the tool I48 may be positioned in such a manner that both front and side cutting edges I48a and H811 will contact the wheel face when the corresponding edges I54a and I54b of the template I 54 are abutting the stop bar I08.

With the above adjustments correctly made and with the rotary and oscillatory motion of the grinding wheel, it will be readily apparent that rotating the tool holder I I5 on the table I6 from the position where the front cutting edge I48a is flush with the wheel face to the position where the side cutting edge is flush, that a radius equal to the adjustment of the wheel face from the normal position will be ground on the nose of the tool I 48 tangent to both cutting edges i480 'and I48b as represented in Fig. 14 by an arc a-b.

For extreme accuracy these adjustments may be made with a dial indicator held in a fixed position relative to the tool holder base 8. In order to make adjustments by dial readings, it is necessary to know the exact value in linear measurement of the adjustments. These values can be readily computed in the following manner. To position the tool I48 for grinding the radius as indicated in Fig. 14 by dotted lines, it is necessary to adjust the tool along the path A-A. As there are only two ways to adjust the tool and these ways take the directions along lines XX and Y-Y, it is necessary to compute the value of the distances B-A and AB respectively.

As shown in Fig. 14 angles are noted as follows:

D=included edge angle E=front edge angle Then the length of adjustment along Y-Y is equal to And the length of adjustment along XX is equal to BA AA Xsme G or BA F Using the completed master tool I48 as a template, the template I54 should then be reground in the usual manner. The grinding wheel 41 is reset to its former position with its operative face midway between the plane of the calibrating block I08 and the stop bar I09. The tool holder II5 is set on the step block 205 (Fig. 15) and the tool holder slide- I I8 adjusted laterally to a center position with the locating stud I52 in position. Then while maintaining the master tool I48 in engagement with the calibrating block I08, the tool holder II5 is swung to generate a corresponding radius on the template I54 and to regrind the edges thereof. The regroundtem- Xsine G plate I54 is now ready to be used to regrind cutting tools or to grind new master tools from a blank.

The angle of tilt of the tool holder frame I25 and the degrees of roll of the sleeve I35 are noted so that the tool holder II5 may be readily set 78 up for regrinding tools in accordance with a given 13 template. For regrinding tools to correspond with a master shape, it is merely necessary to apply the proper template to the tool holder I It, then to set the angle of tilt and degrees of roll so that the tool may be reground having predetermined edge angles and clearance angles.

It will be readily apparent from the foregoing disclosure that a master tool and template may be readily generated from predetermined specifications. Templates may be readily produced from master tools, and new tools ground and worn tools reground accurately with predetermined edge angles and clearance angles.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. Ina tool grinding machine having a rotatable grinding wheel, a transversely movable slide therefor, a work table adjacent thereto, a pivotally mounted frame on said slide to support said wheel, means including a cam to oscillate said frame, driving means including an electric motor simultaneously to rotate said grinding wheel and to rotate said cam to oscillate said frame, a stop bar parallel to and spaced to the rear from the grinding wheel face, a tool holder adapted to slide on said table, a hollow tool supporting sleeve rotatably mounted on said holder, means adjustably to tilt said sleeve in a vertical plane to position a tool to be ground for grinding a predetermined clearance on the end face of said tool, means precisely to rotate said sleeve about its axis to position the tool for grinding a predetermined side clearance on the tool, and a master template on said holder which is arranged to engage the stop bar to facilitate grinding a predetermined shape on the tool being ground, said rotating and oscillating grinding wheel serving to impart the desired grinding action on the tool being ground while the tool holder is moved {with the template in engagement with the stop 2. In a tool grinding machine having a base, a rotatable grinding wheel having a plane operative face, a transversely movable slide on said base, a pivotally mounted frame on said slide to support said wheel, means including a cam to oscillate said frame, means including an electric motor to rotate said grinding wheel and to rotate said cam so as to oscillate said frame and grinding wheel, a feeding mechanism to feed said slide transversely, a table on said base adjacent to said wheel face, a pivotally mounted arm, a calibrating block on said arm having a plane face spaced in front of the wheel face, said arm serving to move the calibrating block to and from an operative position, a step block on said table, a tool holder on said step block having a hollow sleeve to support a master tool in operative engagement with said calibrating block, means adjustably to tilt said sleeve in a vertical plane, means adjustably to rotate said sleeve about its axis to precisely position said master 7 Number 14 tool for a template grinding operation, and'a template on said holder which is ground to a predetermined shape by the rotating oscillating grinding wheel while the tool holder is moved on the step block with the master tool in engagement with the calibrating block,

3. In a tool grinding machine having a base, a rotatable grinding wheel having a plane operative face, a table on said base adjacent to said wheel face, a transversely movable slide for said wheel, -a feeding mechanism to feed said slide toward and from the table, a stop bar on said base which is arranged parallel with the grinding wheel face, a tool holder slidably mounted on the table, a hollow sleeve on said tool holder to support a master tool to be ground, means to tilt and roll said sleeve so as to position a tool being ground for grinding predetermined clearance angles thereon, and a protractor head having an adjustable blade on said tool holder to facilitate grinding predetermined edge angles on a master tool with the tool holder moved on the table to position the protractor blade in engagement with the stop bar.

4. In a tool grinding machine having a base, a transversely movable slide thereon, a pivotally mounted frame on said slide, a rotatable grinding wheel on said frame having a plane operative face, said frame being arranged to swing in a direction normal to the wheel axis, means including a cam to oscillate said frame, yieldable means to maintain said frame in operative engagement with said cam, a motor on said slide, driving connections between said motor and the grinding wheel to rotate said wheel, independent driving connections between said motor and said cam to oscillate said frame and grinding wheel. a nut and screw feed mechanism for adjusting said slide transversely relative to said base, a work table adjacent to said grinding wheel, a stop bar parallel to and spaced to the rear from the grinding wheel face, a tool holder adapted to slide on said table, said tool holder serving precisely to position a tool to be ground, and a template on said holder which is arranged to engage the stop bar to facilitate grinding a predetermined shape on the tool being ground, said rotating and oscillat ing grinding wheel serving to impart the desired grinding action on the tool being ground while the tool holder is moved with the template in engagement with the stop bar.

STEWART S. MADER.

REFERENCES CITED The following references are of record in the file of this patent:

rmrrsp STATES PATENTS Name Date Taylor Aug. 11, 1896 Lumsden' Sept. 9, 1913 Munthe Oct. 3, 1922 Miller Mar. 22, 1927 Bayley June 23, 1931 Bura Aug. 7, 1945 Whipple .L Aug. 26, 1947 Mader June 12, 1949 FOREIGN PATENTS Country Date France Mar. 25, 1935 Number 

